U.S. patent application number 12/808720 was filed with the patent office on 2011-02-17 for production of moldings for foundry purposes.
This patent application is currently assigned to ITN NANOVATION AG. Invention is credited to Christian Goebbert, Michael Hanisch, Volker Hofmann, Magnus Jundt, Frank Meyer, Ralph Nonninger, Christian Priebe, Henning Rehse, Gunther Schaffer.
Application Number | 20110036528 12/808720 |
Document ID | / |
Family ID | 40451304 |
Filed Date | 2011-02-17 |
United States Patent
Application |
20110036528 |
Kind Code |
A1 |
Goebbert; Christian ; et
al. |
February 17, 2011 |
PRODUCTION OF MOLDINGS FOR FOUNDRY PURPOSES
Abstract
A process for producing a mold includes introducing a
composition including a particulate, refractory material and a
binder into a hollow model having an interior cavity which
determines contours of all surfaces of the mold or a mold part,
wherein the model includes at least two separate parts to permit
removal of the mold, and applying a second composition containing
at least one organosilicon component and at least one solvent to at
least one of the separable parts before use.
Inventors: |
Goebbert; Christian;
(Blankenburg, DE) ; Hanisch; Michael;
(Spiesen-Elversberg, DE) ; Hofmann; Volker;
(Nalbach, DE) ; Meyer; Frank; (Saarbrucken,
DE) ; Nonninger; Ralph; (Saarbrucken, DE) ;
Rehse; Henning; (Wermelskirchen, DE) ; Jundt;
Magnus; (Freilassing, DE) ; Priebe; Christian;
(Wulfrath, DE) ; Schaffer; Gunther; (Dusseldorf,
DE) |
Correspondence
Address: |
IP GROUP OF DLA PIPER LLP (US)
ONE LIBERTY PLACE, 1650 MARKET ST, SUITE 4900
PHILADELPHIA
PA
19103
US
|
Assignee: |
ITN NANOVATION AG
Saarbrucken
DE
ASHLAND-SUEDCHEMIE-KERNFEST GMBH
Hilden
DE
|
Family ID: |
40451304 |
Appl. No.: |
12/808720 |
Filed: |
December 19, 2008 |
PCT Filed: |
December 19, 2008 |
PCT NO: |
PCT/EP2008/010971 |
371 Date: |
November 2, 2010 |
Current U.S.
Class: |
164/23 ; 164/159;
164/228 |
Current CPC
Class: |
B22C 1/14 20130101; B22C
9/18 20130101; B29C 33/64 20130101 |
Class at
Publication: |
164/23 ; 164/159;
164/228 |
International
Class: |
B22C 9/02 20060101
B22C009/02; B22C 11/00 20060101 B22C011/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 21, 2007 |
DE |
10 2007 063 552.6 |
Mar 20, 2008 |
DE |
10 2008 015 966.2 |
Claims
1-28. (canceled)
29. A process for producing a mold comprising: introducing a
composition comprising a particulate, refractory material and a
binder into a hollow model having an interior cavity which
determines contours of all surfaces of the mold or a mold part,
wherein the model comprises at least two separate parts to permit
removal of the mold; and applying a second composition containing
at least one organosilicon component to at least one of the
separable parts before use.
30. The process as claimed in claim 29, further comprising:
introducing a composition comprising the particulate, refractory
material and the binder through at least one feed opening into the
interior cavity; curing the binder; and removing the mold.
31. The process as claimed in claim 29, wherein the composition
comprising the organosilicon component is applied such that walls
of the interior cavity are partly or completely covered with a
layer of the composition.
32. The process as claimed in claim 29, wherein the composition
comprising the organosilicon component is cured after introduction
into the interior cavity.
33. The process as claimed in claim 32, wherein curing the
composition is effected thermally.
34. The process as claimed in claim 29, wherein the particulate,
refractory material is sand.
35. The process as claimed in claim 29, wherein the organosilicon
component is at least one member selected from the group consisting
of crosslinkable silanes, siloxanes and silicone compounds.
36. The process as claimed in claim 29, wherein the composition
containing the organosilicon component comprises at least one
alkoxysilane.
37. The process as claimed in claim 36, wherein the composition
containing the organosilicon component comprises
trimethylethoxysilane or trimethylmethoxysilane.
38. The process as claimed in claim 29, wherein the organosilicon
component comprises at least one silane having halogen-containing
side chains.
39. The process as claimed in claim 38, wherein the silane having
halogen-containing side chains is at least one alkylalkoxysilane
having fluorine-containing side chains.
40. The process as claimed in claim 39, wherein the silane having
halogen-containing side chains is
tridecafluoro-1,1,2,2-tetrahydrooctyl-1-triethoxysilane.
41. The process as claimed in claim 29, wherein the composition
containing the organosilicon comprises at least one further
crosslinkable organic component which is not an organosilicon.
42. The process as claimed in claim 41, wherein the at least one
further crosslinkable organic component is a polyester
component.
43. The process as claimed in claim 41, wherein the organosilicon
component and the one further crosslinkable organic component are
present as silicone polyester resin in the composition.
44. The process as claimed in claim 29, wherein the composition
containing the organosilicon component has at least one mold
release agent.
45. The process as claimed in claim 43, wherein the mold release
agent is a polysiloxane of the formula
RO--[R'.sub.2Si--O].sub.n--R, where R and R' are each,
independently of one another, an alkyl radical having from 1 to 8
carbon atoms or an aromatic radical having from 6 to 20 carbon
atoms.
46. The process as claimed in claim 29, wherein the composition
containing the organosilicon component has inorganic particles.
47. The process as claimed in claim 29, wherein the inorganic
particles have particle sizes in the nanosize range.
48. The process as claimed in claim 46, wherein the particles are
silicate particles.
49. The process as claimed in claim 29, wherein the composition
containing the organosilicon component has at least one component
suitable as a crosslinker.
50. The process as claimed in claim 49, wherein the crosslinker is
triethoxysilane (TEOS).
51. The process as claimed in claim 29, wherein the composition
containing the organosilicon component has at least one
catalyst.
52. The process as claimed in claim 51, wherein the catalyst is an
acid.
53. The process as claimed in claim 29, wherein the composition
containing the organosilicon component has at least one organic
solvent.
54. An apparatus for producing molds for foundry purposes, in
particular mask molds or sand cores, comprising at least one part
which is provided with an organosilicon layer or coating.
55. The apparatus as claimed in claim 54, wherein the layer or
coating has a thickness in the range from 1 .mu.m to 100 .mu.m.
56. The apparatus as claimed in claim 54, wherein the layer or
coating has an organosilicon matrix in which inorganic particles
are embedded.
Description
RELATED APPLICATIONS
[0001] This is a .sctn.371 of International Application No.
PCT/EP2008/010971, with an international filing date of Dec. 19,
2008 (WO 2009/083201 A1, published Jul. 9, 2009), which is based on
German Patent Application Nos. 10 2007 063 552.6, filed Dec. 21,
2007, and 10 2008 015 966.2, filed Mar. 20, 2008, the subject
matter of which is incorporated by reference.
TECHNICAL FIELD
[0002] This disclosure relates to a process for producing molds for
foundry purposes, in particular, mask molds, sand cores and parts
thereof, and compositions and apparatuses suitable for use in this
process.
BACKGROUND
[0003] In foundry technology, heat-resistant molds which can be
produced, in particular, from a particulate, refractory material
and a binder are required.
[0004] Molds used for foundry purposes are frequently mask molds
which can be produced by the Croning process (named for its
inventor Johannes Croning). In general, mask molds consist of two
halves which when placed together form a mold material shell
corresponding to the contour of the model. Mask molds and parts
thereof are preferably produced from mixtures of sand and synthetic
resin using heated modeling apparatuses. The mixture is introduced
into a hollow model whose inner cavity determines the contours of
all surfaces of the mold to be produced or of the mold part to be
produced. As a result of the action of heat during molding, the
synthetic resin binder cures to form a self-supporting, mask-like
mold of preferably low thickness which defines the exterior contour
of the product to be cast. In the subsequent casting process, this
mold can be, for example, backfilled with granular material.
[0005] To produce cavities in the interior of foundry products,
cores which can be arranged within a casting mold and whose
exterior shape corresponds to the interior contour of the product
to be cast are required. The core may thus be a constituent of a
mold. After casting, the core can be removed again (dissolved out)
from the cast product.
[0006] Like mask molds, cores are usually produced from a
particulate, refractory material and a binder. For example, in the
core shooting process, sand admixed with binder (known as core
sand) can be introduced under defined pressure and at defined
temperature into a core box (an apparatus which generally consists
of two parts of the mold or mold halves which during use enclose at
least one interior cavity known as a mold cavity having the shape
of the core to be manufactured). After curing the binder, the
finished core (which on the basis of its composition is usually
referred to as a sand core) can be removed from the core box and
used for its intended purpose.
[0007] Since chemical reactions between the liquid metal and the
mold are not allowed to occur in the production of cast metal
products, mask molds and cores usually have to be made from very
high quality materials, e.g., from pure silica sand. The particle
size of the materials is preferably selected so that the surfaces
of the cast products do not become too rough.
[0008] In general, organic binders such as liquid phenolic, furan
and amino resins (or a combination thereof) are used as binders.
With addition of a hardener such as ammonium stearate, a mixture
thereof with a suitable particulate, refractory material can cure
in a very short time at temperatures in the range from 200.degree.
C. to 270.degree. C. However, inorganic binders have been used to
an increasing extent in recent times. Possible binders of this type
are, in particular, water glass, magnesium sulfate, sodium
phosphate, clays, montmorillonite, glauconite, kaolin, aerogels,
cement or gypsum plaster. In addition, sheet minerals, in
particular, sheet silicates, are generally also suitable as
inorganic binders.
[0009] However, both when using organic binders and when using
inorganic binders, problems frequently occur. Thus, adhesion of the
mixture of the particulate, refractory material and the binder to
the walls of the abovementioned interior cavities frequently
occurs. Over time, ever thicker caked material is formed and leads
to inaccuracies in the moldings, which are later reflected in the
finished cast product.
[0010] It is known that such adhering material or caked material
can be avoided by means of "Quickpads." A Quickpad is an
antiadhesion sticker which can, for example, be based on a Teflon
layer. This has to be manually stuck on in the interior cavity and
removed again and replaced when the effect diminishes, which is
associated with a relatively high outlay. In addition, such
Quickpads have only limited use since the very complex contours
occurring in some regions of the interior cavities may make their
use impossible. In addition, Quickpads have only limited thermal
stability and are therefore unsuitable for use in heat-curing
processes.
[0011] As an alternative to the Quickpad, it is known that
single-use mold release agents, in particular, ones based on wax,
can be used. Such mold release agents form a liquid film on walls
of the interior cavities. However, they frequently remain
ineffective in critical regions since the mixture of the
particulate, refractory material and the binder is frequently under
high pressure when it enters hollow models and core molds and the
mold release agent is thereby mechanically washed off.
[0012] It could therefore be helpful to provide an improved
industrial solution for the production of molds, in particular,
mask molds and cores, for foundry purposes, in which the
abovementioned problems do not occur.
SUMMARY
[0013] We provide a process for producing a mold including
introducing a composition including a particulate, refractory
material and a binder into a hollow model having an interior cavity
which determines contours of all surfaces of the mold or a mold
part, wherein the model includes at least two separate parts to
permit removal of the mold, and applying a second composition
containing at least one organosilicon component to at least one of
the separable parts before use.
DETAILED DESCRIPTION
[0014] Selected preferred features may be explained in detail
hereinafter only in the description of one of the abovementioned
subjects. However, the corresponding explanation is nevertheless
intended to apply to all subjects. The wording of all claims is
hereby incorporated by reference into this description.
[0015] Our process produces molds for foundry purposes,
particularly preferably mask molds, cores (in particular, sand
cores) and parts thereof. The process thus allows production both
of molds which define the exterior contour of a product to be cast
and of molds which can be used for creating a cavity (cores).
[0016] In the process, a composition comprising a particulate,
refractory material and a binder is introduced, in particular
blown, into a hollow model. After the introduction, the binder is
generally immediately cured, whereupon the molds produced can be
removed. The interior cavity of the hollow model or its shape
determines the contours of all surfaces of the mold to be produced
or the core to be produced. The mold itself includes at least two
parts which can be separated from one another to permit removal of
the mold. To produce sand cores, preference is given to using a
conventional mold box or a conventional mold flask, as are known in
the art.
[0017] A process for producing molds for foundry purposes is
particularly characterized in that a composition containing at
least one organosilicon component and preferably at least one
solvent is applied to at least one of the separable parts before it
is used.
[0018] A process for producing cores for foundry processes
preferably comprises: [0019] introduction, in particular, shooting,
of a composition containing a particulate, refractory material and
a binder (the composition preferably consists essentially of the
particulate, refractory material and the binder) through at least
one feed opening into the interior cavity, [0020] curing of the
binder, and [0021] removal of the mold.
[0022] The composition comprising the organosilicon component is
preferably applied in such a way that the walls of the interior
cavity are at least partly, preferably completely, covered by the
layer or coating. In particular, the composition is applied in the
regions which are particularly severely mechanically stressed
during introduction of the composition comprising the particulate,
refractory material and the binder, i.e., particularly the regions
which are located opposite the at least one feed opening and are
thus struck directly by the composition during shooting-in.
[0023] The composition is preferably applied by spraying on or
dipping. It is naturally necessary to use a composition having a
suitable consistency in each case. The properties required for this
and also other properties of the composition can be adjusted by
addition of appropriate additives such as thickeners, rheological
additives and the like. Suitable additives are known and require no
detailed explanation.
[0024] The composition comprising the organosilicon component can
be cured immediately after application. Curing of the composition
is preferably carried out thermally, more preferably at
temperatures in the range from room temperature to 350.degree. C.,
particularly preferably from 20.degree. C. to 300.degree. C., in
particular from 30.degree. C. to 200.degree. C.
[0025] In this case, the composition preferably comprises at least
one constituent which can be crosslinked thermally. This can also
be, in particular, the at least one organosilicon component.
[0026] Preferably, curing can also be effected by electromagnetic
radiation. The use of radiation having wavelengths in the UV and/or
IR region is particularly preferred.
[0027] In this case, the composition preferably comprises at least
one constituent which can be crosslinked by radiation. Thus, for
example, the at least one organosilicon component can have side
chains which can be crosslinked by radiation (in particular, chains
having ethylenic double bonds).
[0028] It is in principle also possible for curing to be carried
out both thermally and by using radiation. Thus, components which
can be crosslinked thermally and components which can be
crosslinked by radiation can both be present in the composition, in
which case it is not necessary for all components to be
organosilicon components. Thus, for example, polyester resins can
also be preferred as a constituent of the composition.
[0029] The organosilicon layer or coating produced in this way has
an excellent release function and effectively prevents direct
contact of the composition comprising the particulate, refractory
material and the binder with at least the critical wall regions of
the interior cavity. The layer or coating can therefore also be
referred to as release layer. It has high nonwettability. In
addition, it is characterized, in particular, by an extraordinarily
high abrasion resistance and very good adhesion properties.
[0030] The particulate, refractory material is particularly
preferably sand, especially silica sand.
[0031] As binders for the particulate, refractory material, it is
possible to use the organic binders mentioned at the outset.
However, it is also possible to use inorganic binders, optionally
in combination with one or more organic binders. Possible inorganic
binders are, in particular, water glass, magnesium sulfate, sodium
phosphate, clays, montmorillonite, glauconite, kaolin, aerogels,
cement, gypsum plaster, sheet minerals such as sheet silicates and
combinations of the components mentioned.
[0032] As mentioned above, we use a composition containing at least
one organosilicon component and preferably at least one solvent for
producing molds for foundry purposes and parts thereof, in
particular, in a process for producing molds for foundry
purposes.
[0033] The at least one organosilicon component is preferably a
crosslinkable component and thus comprises compounds which can
undergo reactions with one another on irradiation and/or on
heating. It particularly preferably comprises a silane or a
siloxane or a crosslinkable silicone compound. Combinations of
silanes and siloxanes or silicones can also be used.
[0034] Particularly suitable silanes are organofunctional silanes
such as aminosilanes, epoxysilanes and methacryloxysilanes and
isocyanatosilanes. Preferably, the methacryloxysilanes are, in
particular, radiation-crosslinkable silanes which can be cured, for
example, by UV radiation as has been discussed above.
[0035] Suitable siloxanes and silicones are, for example,
polysiloxanes such as, in particular, polydialkylsiloxanes (in
particular, polydimethylsiloxane), polyorganosiloxanes,
epoxysilicones and polyether silicones. These should each have
crosslinkable groups. The crosslinkable groups can be, for example,
groups such as free hydroxy groups which can undergo a condensation
reaction or, for example, alkoxy groups from which free hydroxy
groups can be formed.
[0036] Furthermore, it is preferred that the composition has
further organosilicon components. In particular, alkoxysilanes are
preferably present. Among the particularly preferred alkoxysilanes,
particular mention may be made of alkylalkoxysilanes such as
trimethylethoxysilane or trimethylmethoxysilane.
[0037] In summary, a composition thus contains, in preferred form,
at least one of the above-mentioned crosslinkable organosilicon
compounds and additionally at least one alkoxysilane.
[0038] Furthermore, the composition can contain at least one silane
having halogen-containing, preferably fluorine-containing, side
chains, in particular, as at least one crosslinkable organosilicon
component. This is particularly preferably an alkoxysilane having
halogen-containing, in particular, fluorine-containing, side
chains, particularly preferably
tridecafluoro-1,1,2,2-tetrahydrooctyl-1-triethoxysilane.
[0039] A composition containing both such a silane having
halogen-containing side chains and an alkylalkoxysilane is
described in the examples.
[0040] Apart from the at least one crosslinkable organosilicon
component, a composition which can be used can also comprise at
least one further crosslinkable organic component which is not of
an organosilicon nature, in particular, a polyester component.
[0041] Particularly preferably, the at least one crosslinkable
organosilicon component and the at least one further crosslinkable
organic component are present in combination as silicone polyester
resin in the composition. Suitable silicone polyester resins are,
for example, commercial polyester-modified methyl-phenyl-silicone
resins which are also suitable for coating of baking molds for
easier removal of bakery products from molds.
[0042] Furthermore, it is preferred that the composition comprising
the at least one organosilicon component has one or more mold
release agents, in particular, at least one release oil. The mold
release agent is preferably a linear or branched polysiloxane, in
particular, a polysiloxane of the formula
RO--[R'.sub.2Si--O].sub.n--R, where R and R' are, independently of
one another, an alkyl radical having from 1 to 8 carbon atoms or an
aromatic radical having from 6 to 20 carbon atoms.
[0043] Preferably, inorganic particles, in particular, particles
having particle sizes in the range from nanometers to microns, can
also be present in the composition comprising the at least one
organosilicon component. The nature of the inorganic particles is
not critical and all ceramic particles are fundamentally suitable.
However, silicate particles are particularly preferred. It has
surprisingly been found that the presence of such particles
significantly increases the abrasion resistance of the release
layer.
[0044] As further components, a composition comprising the at least
one organosilicon component has components suitable as
crosslinkers. Customary crosslinkers are known to those skilled in
the art. Particular preference is in the present case given to
using triethoxysilane (TEOS) or triacetoxymethylsilane.
[0045] In addition to the crosslinker or as an alternative thereto,
a composition can also have a catalyst, in particular, at least one
condensation catalyst. This can be, for example, an acid such as
hydrochloric acid or sulfuric acid.
[0046] The abovementioned solvent is preferably an organic solvent,
in particular, at least one alcohol, ether and/or ester. Nonpolar
solvents such as petroleum spirit can also be used. However, the
nature of the solvent is in principle not critical.
[0047] An apparatus for producing molds for foundry purposes is
particularly suitable for producing mask molds and sand cores. It
has at least one part which is provided with an organosilicon layer
or coating, in particular, a cured organosilicon layer or coating.
The apparatus is accordingly itself preferably a mold.
[0048] The layer or coating is preferably produced from a
composition containing at least one organosilicon component and
preferably at least one solvent, as has been comprehensively
described above.
[0049] Preferably, the layer or coating has a thickness in the
range from 1 .mu.m to 100 .mu.m, in particular, from 1 .mu.m to 20
.mu.m.
[0050] The at least one part preferably consists at least partly,
preferably also entirely, of metal and/or plastic.
[0051] The layer or coating is particularly preferably permanently
or at least semipermanently bound to the at least one part of the
mold. Preferably, the bond is so strong that the layer cannot be
detached without destruction. On the surface of the at least one
part, the layer or coating forms an organosilicon matrix in which
inorganic particles can be embedded in preferred forms.
[0052] Further features can be derived from the examples. Here,
individual features can in each case be realized either on their
own or as a combination of a plurality thereof in one form. The
preferred forms described serve merely for the purposes of
illustration and to give a better understanding and do not
constitute any restriction.
EXAMPLE 1
Production of a Composition A
[0053] In a 1000 ml flask, 500 g of a polyester-modified
methyl-phenyl-polysiloxane resin admixed with a release substance
(for example, a commercial polyester-modified
methyl-phenyl-polysiloxane resin suitable for removal of
sugar-containing bakery products from molds) and 500 g of
methoxypropyl acetate as solvent (possibly colored blue with
ultramarine blue extra dark) are mixed with one another and the
mixture is stirred at RT for one hour. Depending on the desired
layer thickness, dilution in a ratio of from 2:1 to 1:2 is
possible. After stirring at RT for 4 hours, the product is ready to
use and can be applied by spraying.
EXAMPLE 2
Production of a Composition B
Composition:
TABLE-US-00001 [0054] Raw material % 2-Propanol 93.8425 Silane
having fluorine-containing side chains 2.49 TEOS (Dynasyl A)
Tetraethoxysilane 2.035 Trimethylethoxysilane 0.5775 Hydrochloric
acid 0.1 mol/l 1.055
[0055] The alcohol is placed in a 1000 ml glass flask. The silane
having fluorine-containing side chains
(tridecafluoro-1,1,2,2-tetrahydrooctyl-1-triethoxysilane), the TEOS
and the trimethylethoxysilane are added in succession over a period
of one hour from a dropping funnel while stirring vigorously. The
hydrochloric acid is then added dropwise. After stirring at room
temperature for 4 hours, the hydrolysis product is ready to be used
and can be applied.
EXAMPLE 3
Production of a Composition C
TABLE-US-00002 [0056] Raw material % 2-Propanol 93.76 Silane having
fluorine-containing side chains 2.55 Colloidal silicate dispersion
3.59 Conc. sulfuric acid 0.10
[0057] The alcohol is placed in a 100 ml glass flask. The silane
having fluorine-containing side chains
(tridecafluoro-1,1,2,2-tetrahydrooctyl-1-triethoxysilane) and the
colloidal silicate dispersion (silicate dispersion in isopropanol
having a particle size of about 13 nm and a solids content of 30%)
are added in succession over a period of one hour from a dropping
funnel while stirring vigorously. The sulfuric acid is then added
dropwise. After stirring at RT for 4 hours, the product is ready to
use and can be applied.
EXAMPLE 4
Processing of Composition A
[0058] In preparation, the parts to be coated (e.g., stainless
steel test plates having a size of 5 cm.times.15 cm as test
substrates) are preferably cleaned with isopropanol. As an
alternative or in addition, the parts can also be cleaned by sand
blasting.
[0059] The product A from Example 1 is applied by means of a spray
gun (e.g., SATA minijet 4 HVLP having a 0.8 nozzle) at 2 bar. The
layer thicknesses achieved are in the range from 3 .mu.m to 75
.mu.m. Curing is carried out (in a drying oven) at from 150.degree.
C. to 230.degree. C. over a period of from 1 to 4 h.
EXAMPLE 5
Processing of Compositions B and C
[0060] The products B and C from Examples 2 and 3 are applied by
means of a cloth (preferably cleanroom cloth, e.g., Betawype TX
2009 from Texwype) and rubbed in (polished). Thermal setting is
carried out at 200.degree. C. by means of a hot air blower over a
period of from 1 to 3 minutes, preferably 90 s, or (in a drying
oven) 1-4 h at 150-190.degree. C., preferably 2 h at 190.degree.
C.
EXAMPLE 6
[0061] In an automotive foundry, a core flask having 20 engravings
was treated with the product A. Here, the critical regions (places
opposite the shooting-in nozzles for the core mold material) were
treated with the product. The product was applied and allowed to
cure at room temperature for 24 hours. The core flask was then used
in mass production. It was found that the time until critical
caking of core mold material occurred could be tripled.
EXAMPLE 7
[0062] In a foundry, the parts of a hollow model for producing
exterior molds for the casting of sanitary fittings were treated
with the product A. Product A was applied in such a way that the
walls of the interior cavity of the hollow model were completely
coated with a thin layer of the product. The product was
subsequently allowed to cure at room temperature for 24 hours. The
mold was then used in mass production. Even after the hollow model
had been used a number of times, no critical caking of mold
material was observed.
EXAMPLE 8
[0063] In an automotive foundry, a mold box made of metal having
two engravings was treated with the product A. In the case of one
engraving, the critical regions (places opposite the shooting-in
nozzles for the core mold material) were treated with the product.
The product was applied and allowed to cure at room temperature for
24 hours. The second engraving was covered by sticking on a
Quickpad (adhesive film having a non-stick effect). The mold was
then used in mass production. It was found that the time until
critical caking of core mold material occurred is identical for the
two methods.
* * * * *